Bad Logic in Preset Saving

Seeing this ticket: http://drupal.org/node/521860

I realized that my code has bad logic in it. When editing coded presets, I wanted to be able to account for the parts of the map array that were not available in the UI, so there is a map merge when submitting that brings in the original map. But this makes it an additive process, meaning that if I take away something in the UI, then it will be added back with the map merge.

I am thinking there needs to be some more manual massaging, unfortunately. It isn't a simple case of removing any fields that are in the UI, because something like layers can have both coded and layers provided by hooks.